Conventionally, as an electric contact of the type mentioned above, there is known a contact pin provided for an IC socket as a socket for an electrical part. This IC socket is disposed on a circuit board and accommodated with an IC package as an object to be inspected, and a terminal of this IC package and an electrode of the circuit board are electrically connected through the contact pin.
The contact pin has an outermost Au plated layer (added with extremely small amount of Co) and a base layer made of Ni. On the other hand, the terminal of the IC package is made of Sn (tin) as main component including no lead, so-called lead-free solder. According to the contact of the contact pin and the terminal, they are connected electrically, which are then provided for a burn-in test.
As such kind of electric contact, there is disclosed in Patent Publication 1 (Japanese Patent Publication No. 2005-504962 A)